The present invention relates to a method for collecting and referencing information as to the processing history in a data processing system, and in particular, to a system for distributing an online journal load by means of a direct access storage devices (to be referred to simply as DASD's hereinafter) suitable for an online system having a considerably high traffic.
In an online journal system in which processing, such as file update, message input and output, and the like operations are carried out, it is an essential factor to increase the reliability for collecting and for referencing information. There have been proposed a variety of systems for collecting information as to the processing history in this kind of data processing system. The data items, however, have been serially collected according to the order of data occurrence on a recording medium. Detailed description of such systems will be found in the U.S. application Ser. No. 536,875, now U.S. Pat. No. 4,652,940 by the present inventor hereby incorporated by reference. In such a system, if a processing system has a high traffic, a DASD such as a disk unit cannot be utilized in place of a magnetic tape unit because the input/output time of a disk unit is several times longer as compared with that of a magnetic tape unit, hence the recording medium is limited to a magnetic tape. In a large online system, for example, that used by a large bank or the like enterprise, the number of data items which are inputted from or outputted to terminal equipment reaches approximately 500 thousand per day. If magnetic tapes are adopted as recording media, at least 25 magnetic tapes (approx.) will be required to be changed each day, which leads to the disadvantage that the operator's load is increased and a deteriorated operability results.